An upper/lower split can last you forever. A lot of massive, strong powerlifters stick with that throughout their entire lifting careers. However, if you’re older and/or have some trouble recovering, you may prefer a push/pull/legs split that has you training everything directly once per week. This is how most famous bodybuilders have trained in the past and many still do.
I HATE that the resistance training community can be so tribal. I have been preaching to bodybuilders for years about the benefits of powerlifting, or Olympic lifting or kettlebells or even Crossfit style conditioning and many have been receptive. Learn from each other and achieve levels of fitness you simply could not have otherwise. Don’t brush off bodybuilding wisdom…it could be the missing factor in your program.